1. Field of the Invention
The invention relates to an automated material handling system, and more particularly to an automated material handling system and method for combining an over-head conveyer with a material control system.
2. Description of the Related Art
With respect to current automated material handling systems (AMHS), a front opening unified pod (FOUP) is transmitted between transport system controllers (TSC) (i.e. semiconductor control devices complying with Semiconductor Equipment and Materials International (SEMI) E82 communication protocol) and can only be transmitted from one transport system controller to another one via stockers. As shown in FIG. 1, a transport system controller 110 must first move a FOUP 200 to a stocker (STK) 400 and a transport system controller 130 can only take the FOUP 200 from the stocker 400.
An arm mechanism (not shown) of the stocker 400 can only transmit a single FOUP or a predetermined number of FOUPs at the same time. Thus, when the transport system controller 110 continuously transmits FOUPs to the stocker 400, excessive loading of the stocker 400 may occur, generating transport bottlenecks which negatively affects transport performance.
Additionally, with respect to current automated transport systems, an over-head conveyer (OHC) is utilized. However, the OHC cannot efficiently control process flow and only provides a connection to a Material Control System (MCS) using a single transport system controller. Further, the automated transport systems do not provide applications for conveyer stocker controllers (CSC).
Thus, an automated material handling system and method for combining an over-head conveyer with a material control system is desirable.